RICHLAND, Wash. -- U.S. Sen. Ron Wyden is at the Hanford Nuclear Reservation today, his first fact-finding tour as new chairman of the Senate Energy and Natural Resources Committee.

The visit has added significance following news last week that
a radioactive waste tank might be leaking up to 300 gallons a year.

The Oregon senator's tour will continue through the afternoon, but started at the B Reactor. U.S. Rep. Doc Hastings, R-Wash., and boosters in Washington's Tri-Cities area want it to become part of a Manhattan Project National Park, commemorating the World War II project that built the world's first atomic bombs.

Some background: The B Reactor is the world's first full-scale nuclear reactor, built in 13 months starting in 1943 by 50,000 construction workers, few who knew exactly what they were building. It was cooled by millions of gallons of Columbia River water.

The reactor produced the plutonium in the Fat Man bomb dropped on Nagasaki Aug. 9, 1945, helping to compel Japanese surrender six days later, but killing 60,000 to 80,000 people within two to four months after the blast.

The reactor shut down in 1968. In 2008, the Department of the Interior designated it as a National Historic Landmark, and the Department of Energy now offers public tours. Some 30,000 tourists have visited since.

Manhattan project sites in Los Alamos, N.M., and Oak Ridge, Tenn., are also included in the proposed national park, which stalled in Congress last year. Supporters hope new Interior Secretary nominee Sally Jewell, president and CEO of Washington-based outdoor gear retailer REI, can help it gain momentum.

Wyden said he supports the proposal, which will come before his committee. Previous cost estimates were $20 million, but Wyden said they'll explore other revenue, including private money. Some might see a park as glorifying the bomb, but Wyden said it's important history and would support a debate about including impacts on Japan as part of the park. "This is history we ought to preserve," he said, "a story that just shouldn't be shunted aside."

Tuesday's tour continues and watch for coverage later on oregonlive.com and in Wednesday's Oregon.